Phonon-assisted carrier cooling in h -BN/graphene van der Waals heterostructures
Abstract
Being used in optoelectronic devices as ultrathin conductor-insulator junctions, detailed investigations are needed about how exactly h -BN and graphene hybridize. Here we present a comprehensive ab initio study of hot carrier dynamics governed by electron-phonon scattering at the h -BN/graphene interface, using graphite (bulk), monolayer, and bilayer graphene as benchmark materials. In contrast to monolayer graphene, all multilayer structures possess low-energy optical phonon modes that facilitate carrier thermalization. We find that the h -BN/graphene interface represents an exception with a comparatively weak coupling between low-energy optical phonons and electrons. As a consequence, the thermalization bottleneck effect, known from graphene, survives hybridization with h -BN, but is substantially reduced in all other bilayer and multilayer cases considered. In addition, we show that the quantum confinement in bilayer graphene does not have a significant influence on the thermalization time compared to graphite and that bilayer graphene can hence serve as a minimal model for the bulk counterpart.
- Publication:
-
Physical Review B
- Pub Date:
- June 2022
- DOI:
- 10.1103/PhysRevB.105.245419
- arXiv:
- arXiv:2108.12894
- Bibcode:
- 2022PhRvB.105x5419B
- Keywords:
-
- Condensed Matter - Mesoscale and Nanoscale Physics;
- Condensed Matter - Materials Science
- E-Print:
- 6 figures, journal article